Mucus-munching enzyme discovery may help identify intestinal diseases

11 Aug 2020

Image: © nobeastsofierce/

Researchers have discovered an enzyme in bacteria that breaks down mucus in the gut and could help produce new diagnostics for intestinal diseases.

An essential enzyme has been discovered by researchers from the University of Birmingham and Newcastle University, which could one day spell good news for those with intestinal issues. Writing in Nature Communications, the researchers said they have successfully identified and characterised one of the key enzymes found in gut bacteria.

They demonstrated how the enzyme enables bacteria to break down and feed off sugars in the layers of mucus lining the gut. This research offers a potentially significant step forward in our understanding of the complex co-dependent relationships at work in the gut, about which little is currently known.

As the mechanism used by the enzyme is so distinctive, researchers hope that this discovery can be used in the development of new diagnostics for intestinal diseases.

Molecules in the gut mucus, called mucins, are constantly generated by the body and layered along the gut. This helps provide a barrier between the gut bacteria and the rest of the body. Mucins contain chains of sugar molecules called glycans, and these also provide an essential source of nutrients for bacteria.

During their research, the scientists looked at how the enzyme sits outside the bacterial cell and chips away at the mucin molecule, and is eventually taken inside the bacterial cell to be consumed. What makes the enzyme potentially important is that glycans are known to change when certain diseases are present in the body.

Therefore, it could be possible to use the enzyme to take a snapshot of the glycans within a biopsy and use that as a biomarker for early detection of disease.

A tree-like structure

“Mucus is structured a bit like a tree, with lots of different branches and leaves,” said Dr Lucy Crouch, who led the research.

“Lots of the enzymes discovered so far might clip away some of the leaves to eat, but the enzyme we studied will clip away a whole branch – that’s quite a distinctive mechanism and it gives us a useful biomarker for studying disease.”

In testing with tissue samples, researchers added the enzyme and labelled the glycans with fluorescent dye. These samples were from people living with ulcerative colitis and colorectal cancer, and from preterm infants with necrotising enterocolitis, a serious illness in which the gut becomes inflamed and can start to die. This test revealed useful information about the glycan structure.

“Although we still don’t fully understand what the glycan structures are made from and how these vary between different tissue types, we can see that the differences in structure between healthy and non-healthy tissue is quite distinctive,” Crouch said.

“We hope to be able to use these enzymes to start producing better diagnostics for the very early stages of these diseases.”

Colm Gorey was a senior journalist with Silicon Republic